A semiconductor package may comprise one or more semiconductor dies that may be attached to a substrate. A die may be both electrically and mechanically coupled to a substrate using, for example, a flip-chip interconnect technique or by wirebonding in conjunction with a die-attach adhesive. A laser drilling system, e.g., CO2 laser drillers, may be used to form microvias in a semiconductor package, e.g., die, substrate or any other component, to form the interconnection between different layers of electrical circuit. For example, a substrate may comprise a multi-layer structure. And, microvias may be used to interconnect circuits on different layers of the substructure. Apertures with one or more openings may be used in the laser drillers to control an intensity of a laser beam. Several factors may impact a size of a microvia, including, e.g., aperture opening, laser wavelength, laser intensity, diffraction of the laser, as well as other factors. The ever-increasing I/O density of integrated circuits may demand a reduced microvia size. For a given laser source, some limitation for microvia size shrinkage may comprise a diffraction of the laser beam through the aperture opening.